In an occupant leg protecting device for a vehicle which is mounted to a vehicle such as an automobile or the like, there has conventionally been known a structure in which a knee bolster which is movable in a vehicle body longitudinal direction is inserted into an opening hole formed in an instrument panel which is fixed to the vehicle body (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 2001-122061). In this structure, after an ignition switch is set in an on state, the knee bolster is displaced, and the distance between the knee bolster and the occupant is maintained at a constant value in a normal state. Further, Japanese Patent No. 2528403 and JP-A No. 2003-54352 are other conventional techniques.